Flushing oil



Patented Jan. 17, 1950 V FLUSHING on. James W. Starrett, Crete, Ill., assignor to Standar'd Oil ,Gompan f I dia a" y, Chicago, 111 "a corporation N Drawing. Application December 29, 1945, Serial No. 638,489

7 Claims. (01. gag-147 2 1 This invention relates primarily to flushing oils and particularly to flushing oils of the type which may be used inthe lubricating system of a motor for aperiod of time in place of the usual lubricating oil.

It isan object of this invention toprovide a flushing'oil {that has improved flushing and solvent'propertie s, making it suitable 'for removing deposits of lacquer, varnish, lacquer-bonded solparticles, sludge deposits, etc., particularly from Di S1 9? fingering grqoves, cylinder walls, crankcase walls, etcfin internal combustion engines. It is a further object to provide such afiushing oil that has suitable lubricating propt pth t i m b us d in the cran caseof an engine without danger of scoring pistons, cylinder walls,hearings,"etcl It is yet a further-object .orthis invention to provide such afiushing oil having suificiently high flash point and initial boiling point to enable its safe use under most conditions. It is yet a further object to provide as a solvent in such a flushing oil, a mixture of hydrocarbons containing polycyclic aromatics and having no carcinogenic properties and thus enabling its safe use under reasonable conditions by unskilled personnel. Other per tinent objects are to provide a flushing oil that is of relatively low viscosity to obtain improved circulation and flushing action in all parts of an engine where dirt may accumulate, and to provide a flushing oil having foaming properties so that the solvent is carried to portions of an engine which would notnormally be reached by conven l u in oi s My improved flushing oil comprises generally a novel solvent, composed principally of monoand polycyclic aromatic hydrocarbons having one or more methyl side chains and having not more than three condensed aromatic rings in which may be mixed as an additive an olefin polymerphosphorus' sulfide reaction product. My preierred solvent is a normall liquid hydrocarbon refractory stock produced by the catalytic conversion of aliphatic and alicyclic hydrocarbons by a process known as hydroiforming and is known as hydroformer polymer or bottoms. It has excellent solvent action on varnishes, lacquers, and sludges of the type encountered in automotive engines. I have found that by adding preferably about 15 of the reaction product, although about 1-20%, and even higher, is suitable, I can produce a flushing oil of relatively low viscosity in the range of about 30 to 60 seconds Saybolt Universal at 100 l t, and preferably off about 32 to 3 5, that can be used in the crankas o lu r ca in enter; of aut m tive as i s w th i d es'r or scqr ng- Th ow vie.- fosity of myfiushirig oilirnprove's its penetrating are an flus n qt the rec. 1. 1"; ca e 92 'i i i redt e ineutrali d f icmoletely r Part a l it es be e flu hin oil foaming propertieswhich serves to carry'the solvent into portions of the engine which would not otherwise be reached when using convene tional flushing oils.

That my flushing oil may be successfully used in th lubricatin sy tem f a moto durin its operation, though of such unusually low viscosity, s a n p c an u r dictab result a tributable, I believe in part, to the unique viscosity properties of my solvent in relation to its boiling range and to the addition to my solvent of the reaction product which, though in such relativel small amounts as to have very little influence on the total viscosity of my flushing oil, prevents scoring. In some cases where a. higher viscosity is desired because of the nature of the lubricating system, such as in Diesel engines, I may obtain any increased viscosity by increasing the ratio of the reaction product, to solvent, or by adding another hydrocarbon oil of a viscosity higher than that of the solvent, such as, for example, an olefin polymer or a blending oil obtained by the distillation of a thermal cracking residue.

Hydroformer polymer is a complex mixture of methylated monoand polyclic aromatics. As an example, a sample having a gravity of about 12.0 A. P. I. has the following composition by volume:

Fraction Components Toluene. Xylenes.

Naphthalene;

Monomethylnaphthalenes.

p enyl.

Dimethylnaphthalcnes.

Methyldiphenyls.

Tnmethylnaphthalenes.

Anthracene and Phenanthrene.

MethylanthracenesandMethylphenanthrenes Pytene.

Tetracyclics and Higher.

12 A. P. I. A. P. I.

Per cent Per cent Methyl and polymethylbenzenes 4 Naphthalene and monomethylnaphthalenes..- 36 Dimethylnaphthalenes 32 16 The tetracyclic and higher condensed aromatics are eliminated by rerunning the hydroformer polymer as produced to an end point of not more than 650 F. and preferably 625 F. in order that the solvent material may be free of these condensed polycyclic aromatics of more than three rings and thus safe from the point of view of possible carcinogenic properties. As a consequence of this rerunning, the proportions of principal constituents in the solvent will be somewhat altered depending on how much material is eliminated upon rerunning.

My preferred solvent is approximately a 90% cut of hydroformer polymer of about 10-1l A. P. I. gravity having the following specifications:

150 to 200 F.

32.6 Seconds Boiling Range Te pclr ature,

Although 300 F. is permissible, I prefer that the initial boiling point of my solvent be at least 350 F. in order to insure that there are no low boiling solvent materials in the resulting flushing oil which may have three definite harmful effects. One such effect, besides that of fire hazard, would be for. the low boiling solvent to dissolve carbonaceous material and then, upon this solution contacting hotter portions of the engine, e. g., at the cylinder walls, where the solvent would be evaporated, depositing the previously dissolved carbonaceous material. Another such eifect of low boiling materials in a flushing oil is that of forming a gaseous film on hot surfaces and thus reducing the efficiency of the solvent action of the normally higher boiling liquid materials; or in other words, forming an insulation against the solvent as well as the flushing action of the main body of the oil.

As pointed out above, the polymer is a product of the well-known hydroforming process described in U. S. 2,335,596, which, in general, comprises treating a virgin or cracked naphtha or a mixture of both with a solid, porous hydroforming catalyst at a temperature in the range of about 850 F. to about 1050 F., preferably in the presence of hydrogen. Suitable catalysts are oxides .ofmetals of groups II to VI of the periodic system, particularly oxides of the VI group metals such as chromium and molybdenum, preferably supported by alumina or magnesia. Excellent catalysts can be prepared by depositing about 4 to 10% molybdena upon an activated alumina. Suitable space velocities for hydroforming fall within the range of about 0.2 to about 4 volumes of liquid charge stock per hour per volume of catalyst space. About 0.5 to about 8 mols of hydrogen can be charged to the process with each mol of naphtha feed stock. The hydroformer polymer is a product of fractionating the reaction product from the hydroforming process and it has a boiling range of 350 F. to about 750 F. The composition of the hydroformer polymer may vary to a minor extent depending upon the specific catalyst, the age of the catalyst, and particularly the type of feed stock. I prefer to use a conventional heavy naphtha feed stock having a gravity of about 40 to 65 A. P. I.

Although I prefer a hydroformer polymer as my solvent, I may use, under some circumstances, fractions of comparable boiling range comprising principally methylated aromatics such as can be obtained from a catalytic cracking refractory stock of the type described in U. S. 2,335,596, the distillation of coal tar, and solvent extracts of various hydrocarbon mixtures.

The reaction product, in general, is preferably a neutralized, wholly or partially, reaction product of .a phosphorus sulfide and a mono-olefinic hydrocarbon polymer having a molecular weight in the range of about 500 to 2000, and preferably 1000. A metal derivative of such a reaction product and also unneutralized reaction products may be used. The reaction products are prepared from mono-olefin polymers resulting from the polymerization of low molecular weight monoolefins, such as isobutylene and isoamylene and/ or the co-polymers obtained by the polymerization of hydrocarbon mixtures containing isomono-olefins and mono-olefins of less than six carbon atoms, and preferably those of four carbon atoms.

The polymers employed are preferably monoolefin polymers, in which the molecular weight ranges from about to 50,000 or more, and preferably from about 500 to about 10,000. The phosphorus sulfide compounds which may be reacted with the polymer are exemplified by PzSz, P285, P487, P453, etc., P285 being the preferred.

As pointed out above, examples of the preparation of the reaction products contemplated herein are set forth in U. S. 2,316,080, but in general a neutralized product may be obtained by treating the unneutralized product, which has a titratable acidity ranging from about 10 to about 50 milligrams K OI-I per gram of product, with a suitable 'alkali'such as a hydroxide, an oxide, or a carbonate or sulfide of an alkali or of an alkaline earth metal or with ammonia, and preferably with KOH. Other specific materials I may use are NaOH, NazCOs, KHCOz, CaO, and NazS. The neutralized product, that is, having at least about 1% of its titratable acidity reduced by reaction with the alkali, may be further treated with 'a heavy metal such as tin, titanium, aluminum, chromium, cobalt,iron, etc., to make a reaction product with a heavy metal constituent.

As heretofore indicated, the flushing oil of this invention is primarily intended to be used in the crankcase of an engine in the place of the normal lubricating oil. The reaction product serves to prevent scoring, 1 suggest, by forming a protective film on hot contacting surfaces from which the solvent in my oil has been completely Volatilized. The method of flushing an engine with this flushing oil calls for running the engine for a period of time with normal lubricating oil until the engine is hot, then the engine is stopped, the lubricating oil drained out of the crankcase and the crankcase filled to about a 50% excess of the normal fill with my improved flushing oil. The engine is again started and run at a fast idle for a period of about one quarter to one-half an hour. Under these conditions the solvent action, as well as the flushing action due to the motion of the relatively low viscosity material over the parts of the engine which have an accumulation of dirt and sludge, quickly remove the varnish, sludge, varnishbonded solids, etc.

The above description of my flushing oil and the preferred components for compounding the same are given by way of example, and it is realized that various modifications will occur to others skilled in the art; therefore, no limitations are intended thereby except as are contained in the following claims.

I claim:

1. A composition consisting of a catalytic reformed naphtha fraction having an ASTM distillation range of from about 300 F. to about 650 F., and comprising predominately of monoand polymethylated aromatic hydrocarbons, and from about 1% to about 20% of a phosphorus and sulfur-containing reaction product of an olefin polymer having a molecular weight of about 150 to 50,000 and a phosphorus sulfide.

2. A flushing oil composition consisting essentially of a catalytic reformed naphtha fraction boiling within the range of from about 300 F. to about 650 F., and composed predominately of monoand polymethylated aromatic hydrocarbons, and from about 1% to about 20% of a neutralized phosphorusand sulfur-containing reaction product of a phosphorus sulfide and an olefin polymer having a molecular weight of about 150 to 50,000.

3. A flushing oil composition consisting of an aromatic solvent boiling within the range of from about 300 F. to about 650 F., and composed predominately of monoand polymethylated benzenes and monoand polymethylated naphthalenes and from about 1% to about 20% of the phosphorusand sulfur-containing reaction product of phosphorus sulfide and a polymer of a monoolefin said polymer having a molecular weight of about to 50,000.

4. A flushing oil composition consisting of a catalytic reformed naphtha fraction having an ASTM distillation range of from about 300 F. to about 650 F., and API gravit of from about 10 to about 13, and composed predominately of monoand polymethylated aromatic hydrocarbons and from about 1% to about 20% of a neutralized phosphorus and sulfur-containing reaction product of a phosphorus sulfide and a monolefin polymer having a molecular weight of at least about 500.

5. A flushing oil composition as described in claim 4 in which the metal is an alkali metal.

6. A flushing oil composition as described in claim 5 in which the alkali metal is potassium.

7. A flushing oil composition as described in claim 4 in which the metal is a heavy metal.

JAMES W. STARRET'I.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,121,326 Pevere June 21, 1938 2,191,089 Barth Feb. 20, 1940 2,262,926 Edgar Nov. 18, 1941 2,279,001 Matheson Apr. 7, 1942 2,316,080 Loane Apr. 6, 1943 2,335,596 Marschner Nov. 30, 1943 2,363,880 Lieber Nov. 28, 1944 2,403,169 Burk July 2, 1946 2,410,613 Ruthruif Nov. 5, 1946 

1. A COMPOSITION CONSISTING OF A CATALYTIC REFORMED NAPTH FRACTION HAVING AN ASTM DISTILLATION RANGE OF FROM ABOUT 300* F. TO ABOUT 650*F., AND COMPRISING PREDOMINATELY OF MONOAND POLYMETHYLATED AROMATIC HYDROCARBONS, AND FROM ABOUT 1% TO ABOUT 20% OF A PHOSPHORUSAND SULFUR-CONTAINING REACTION PRODUCT OF AN OLEFIN POLYMER HAVING A MOLECULAR WEIGHT OF ABOUT 150 TO 50,000 AND A PHSOPHORUS SULFIDE. 